Method of repairing metal castings



Dec. 4, 1962 R. S. FORSYTHE METHOD OF REPAIRING METAL CASTINGS FiledFeb. 18, 1959 Aha/WW5 ilnited grates Patent 3,065,400 METHOD F REPAHRENGMETAL CASTINGS ftonalrl S. Forsythe, 5616 Harriet Ave. 8., Minneapolis,Minn. Filed Feb. 18, 1959, Ser. No. 794,102 17 tClalms. (Cl. 29-402)This invention relates to an improved method for repairing metalcastings, and in particular to metal castings used in internalcornbusticn engines wherein cooling fluids are employed which interferewith the operation and usefulness of the engine when permitted to escapethrough cracks which may develop in such metal castings.

An object of this invention is to provide a method for elfectivelyrepairin cracked metal castings by sealing the crack without employingheat, which warps or distorts the casting and creates residual strainsand stresses in the casting which may later develop into cracks duringuse, and without the use of sealing compounds which tend to clog thecooling system and cause the engine to run hot and develop additionalcracks during use.

Another object is a method of sealing or cutting off cracks in metalcastings with new metal in such a manner as to prevent the passage orseepage of fluid through said cracks and prevent further expansion ofthe crack during use of the casting following repairing thereof.

Still another object is a method of repairing metal casting by means oftapered threaded members which remove the expansion from the crack andtill the crack with new metal to cause sealing thereof and are insertedin such manner as to resist loosening thereof under the strains andvibrations normally encountered in the use of internal combustionengines.

A more specific object is a method of repairing cracked metal castingswherein one or more tapered threaded members are inserted into the crackin such a manner as to take the expansion out of the crack, fill thecrack with sufficient new metal to seal the leak, and cut off the crackto prevent its extending further 'nto the casting.

These and other objects and advantages of my invention will more fullyappear from the following description made in connection with theaccompanying drawings, wherein like reference characters refer to thesame or similar parts throughout the several views, and in which:

FIG. 1 is a bottom plan view of a cracked diesel cylinder head for adiesel type internal combustion engine;

FIG. 2 is an enlarged sectional view of a portion of FIG. 1 taken on theline 22 thereof;

FIG. 3 is a partial plan view of FIG. 2;

FIG. 4 is a sectional view of another type of cracked casting in whichthe crack extends between openings in the casting and method ofrepairing same;

FIG. 5 is a bottom plan View of a casting wherein the crack isassociated with one opening only and method of repairing same;

FIG. 6 is a sectional view of a portion of HG. 5 taken on the line 6@thereof;

FIG. 7 is a top plan view of still another type casting in which thecrack extends between two valve ports and through the fuel injectorhole;

FIG. 8 is a sectional view of FIG. 7 taken on the line 8-8 thereofshowing a method of repairing the crack shown in FIG. 7;

FIG. 9 is a bottom plan view of still another cracked casting and methodof repairing same; and

FIG. 10 is a detail view of a plug used in this invention to repair thecasting.

The types of metal castings and the crack which may occur in them aretoo numerous to be included herein individually. However, the drawingssuffice to illustrate ice some of the more common types of failuresoccurring in metal castings, particularly those relating to dieselengines, and the method of repairing them according to my invention.However, it should be clearly understood that the drawings serve only toillustrate and not to limit. Although the methods of repair shown by thedrawings differ somewhat in application, they all cmbody three basicobjectives of my invention, namely (1) taking the expansion out of thecrack; (2) filling the crack with sufficient new metal to seal the:leak; and (3) cutting off the crack and preventing further extensionthereof into the casting.

To accomplish these objectives and the repair contemplated by myinvention, 1 insert one or more threaded tapered plugs of the typeillustrated in FIG. 10 into the cracks in the manner hereinafter to bedescribed. If these plugs are carefully installed by the methods of myinvention, a satisfactory and successful repair can be accomplishedwithout the use of heat, sealing compounds or devices other than thosetapered threaded plugs. Although the method of repair of my invention isapplicable to many types of metal castings, it is particularly directedto the repair of metal castings employed in internal combustion engineshaving interior passageways containing a cooling fluid, usually water,wherein the crack or failures are associated with one or more openingsin the casting, such as valve ports, piston chambers, injector holes andthe like, and extend through the casting to the water chambers therebypermitting harmful leaking of fluid to occur.

To adequately repair the crack, substantially all of the expansion orplay must be taken out of the crack, the crack must be filled withenough new metal to seal the crack and prevent further leaking, and theorigin of the crack must be cut off or blocked to prevent furtherextension thereof into the casting when the casting is placed in useafter repairing thereof.

A cording to my invention, one or more tapered threaded plugs areinserted directly into the crack generally longitudinally thereof insuitable drilled and tapped holes originating in the wall of the openingassociated with the crack in such fa1hior1 that the plug engages oroverlaps both sides of the crack for its entire length, and fills theentire length or" the crack with a continuous mass of new metal toprevent the fluid from leaking through to the face of the casting. Thetaper of the plug enables the plug to expand the crack and remove allexpansion or play therefrom. The plug also overlaps the crack origin orbase so as to engage the sound metal adjacent the crack origin and cutoff the crack, thereby preventing further extension thereof. Because ofthe nature of these ca1tings and the difficulty of drilling into a crackfrom an opening therein such as a valve port at the angle necessary toaccomplish this type of repair, it is usually neces sary to supplementthe initially inserted plug with one or more additional tapered threadedplugs which overlap or engage at least a portion of the previouslyinserted plug or plugs in the casting to form a fluid tight sealtherebetween and lock the plugs in place to prevent subsequent looseningthereof. To accomplish the soundest and strongest repair possible, theplugs are so installed as to engage a maximum amount of metal in thecasting consistent with accomplishing the three major objectives ofrepair of my invention. To complete the repair, it is sometimesnecessary to insert one or more plugs into the cracks substantiallyvertically or transversely of the length thereof. However, wherepossible, it is preferable to install the plugs longitudinally of thecrack, as this not only reduces the number of plugs which must beinstalled to accomplish the repair, but also better takes the expansionout of the crack and leaves the plugs tightly installed since thegreater the number of threaded plugs inserted, the

aoeaaoo greater the risk of loosening the plugs previously installed inthe crack. The plugs employed are, of course, metallic and are of ametal having thermo-expansion characteristics closely resembling themetal of the casting being repaired. In each type of repair it isobvious that the portion of the plug projecting from any working surfaceof the casting must be cut off and finished to conform to the desiredconfiguration of the casting.

In some instances, hereinafter to be described, the repair may beeffected by combining a plug inserted vertically into the depth of thecrack with one or more plugs installed longitudinally of the crackthrough one or more openings associated therewith, in which the verticaland longitudinal plugs intersect and overlap each other at least inpart. In such a repair, it is usually preferable to insert thelongitudinal or diagonal plugs first, and cut them off in part with thevertical plug, in order that the vertical plug may engage as much metalas possible to efiect maximum strength of repair, for, in internalcombustion engines, the deck surface and the vertical plugs insertedtherein are subjected to more severe strains than the walls of theopenings such as the valve ports therein. With these basic principles inmind, reference is now made to the drawings for further explanation andunderstanding of my invention.

FIGS. 1, 2 and 3 illustrate the method according to my invention ofrepairing a crack it) occurring between valve ports lit and extendingthrough the casting C to the water chamber 12, the particularillustration being that found on diesel type heads such as those made byCum mins and General Motors, where the water chamber 12 consists of anelongate narrow and closed passageway extending substantially the lengthof the casting between the valve port and has a relatively thinly castbase or deck 13, the water chamber being enclosed interiorly by thecasting to permit the existence of an opening between the exhaust portswhich permits the exhaust gases to be exhausted from one side only ofthe engine,

To accomplish the repair contemplated by my invention, I employ one ormore elongated tapered threaded screw or plug members, as bestillustrated in FIG. 10, which are inserted in suitably tapped holes madein the casting. To repair the crack of FIGS. 1, 2 and 3 by the method ofmy invention, a tapered threaded plug 14 is inserted diagonally into thecasting into the crack longitudinally thereof in an appropriately tappedhole from one valve port to another with the plug being in approximatelythe same plane as the crack with /3 to /2 of the cross sectional area ofthe plug overlapping the crack and filling the crack with new metalthrough its entire length between the valve ports and effectivelysealing off the fluid in the cooling chamber from the outside surface orface 13 of the deck. Since the crack It usually extends some distanceinto one or both of the valve ports, it becomes necessary to seal offnot only the outside surface but also the valve ports from fluid leakingthrough the crack from the cooling chamber. To achieve an effective sealin a minimum of time according to my invention, the easiest method wouldbe to insert a single plug which would overlap both sides of the crackfor its entire length to effectively seal the crack and at the same timeextend beyond the origin or base of the crack into the sound metal ofthe casting so as to cut off the crack and further extension thereof.However, due to the small nature of the openings such as the valve portsand the nature of the drilling and tapping equipment necessary in theoperation of my invention, it is virtually impossible to originate anysubstantially horizontally tapped hole any substantial distance into theopening which could accomplish all of the objectives of my repair by useof a single plug since the plug must be inserted diagonally with theangle of inclination approaching the vertical the further into theopening the hole originates. Therefore. the first diagonal plugfrequently does not catch or cut off all of the crack so as to preventleakage into the ports. Therefore, to catch and seal the remainingunsealed portion of the crack, one or more additional plugs such as 15and 16 are necessary to complete the repair. The second plug 15 may beinserted from the opposite port as the first plug, overlapping bothsides of the crack by /z to /3 its diameter as best shown in FIG. 3,being of the same plane as the crack and intersecting and interlockingwith at least a portion of the first plug and cut ting off and sealingadditional ports of the crack extending into the walls of the valveports.

As an alternative, an equally effective method is to insert the secondplug from the same side as the first plug but starting it further intothe crack while permitting it to lap and engage the first plug forsubstantially its entire length. Whether the plugs are inserted from thesame or opposite sides will depend in large part on how far the crackextends into each of the openings or ports. If two plugs are notsufiicient to eifectively seal and cut off the crack, additionaldiagonal plugs may be inserted further into the port, or a third plug 16may be inserted diagonally from the opposing or inner side which is possible in this particular type of casting, so as to overlap and engagethe lower leading ends of the first two plugs and complete the sealingand cut olf operation.

In most instances, the size of the casting and plug and the angle ofinsertion are such as to carry the plug into and through the waterchamber. In such instances, this is usually not only the unavoidableresult, but is usually a desirable one, since it cuts off and seals thecrack at a source adjacent the water chamber, where it is smaller andeasier to repair then at the longer outer periphery thereof. However, insuch instances where the plugs enter the water chamber, care must betaken to avoid more than /2 the cross sectional area of the plug beingin water. This provides a water tight seal and prevents the casting fromexpanding away from the plug when heated during use to break the sealand cause leaking again. The purpose of the taper is to take all of theexpansion out of the crack. If this is not done, the crack will expandwhen heated in use after the repair, loosening the plug and reopeningthe crack. It should be noted that according to the method of myinvention, it is not necessary that the entire fissure created by thecrack be filled with new metal. It is sufficient if enough new metal isadded to seal the leak and upon completion of the repair, it is quitecommon to have exterior portions of the crack still open and exposed.When enough plugs have been inserted to take all of the expansion out ofthe crack, to seal the leak, and the origin or base of the crack hasbeen lapped or cut off to prevent further expansion thereof, the portionof the plug extending into the valve ports are cut off and the ports arerebored to desired dimensions. Sometimes the plugs extending into thewater chamber are such as to obstruct the flow of Water therethrough,which is not desirable, as it causes the engines to run hot and promotesthe formation of additional cracks. In such instances, the water chamberis rebored in whole or in part to remove enough of the plugs in thechamber to permit free passage of fluid therethrough. The addition ofthe plugs not only repairs the crack, but also builds up the deck areaand reinforces it to increase the resistance to subsequent strains andstresses. By inserting the plugs longitudinally of the crack, the repairis not only effected with a minimum number of plugs, but the plugsengage a maximum amount of casting, which insures a stronger and moreenduring repair.

In this type of head shown in FIG. 1, it has been found preferable toinsert the first plug 14 on the side of the cruel: furtherest away fromthe injector port 17.

Where the crack is of the surface variety and does not extend deeplyinto the casting, one plug such as 18 may sutlice to complete the repairas best shown in FIG. 4 and an additional plug 19 may be inserteddiagonally from one of the ports to cut off the leading end of the firstplug to lock the plug in place and/ or cut off the crack if it shouldhave extended somewhat beyond the reach of the first plug.

FIGS. 5 and 6 illustrate the preferred form of repairing a crack whichdoes not extend between and into two adjacent openings or ports, butrather extends across the deck and into one port only, and does notcreate the problem of sealing two vertical craclcs in the port nor doesit enable plugs to be inserted diagonally from either side of the crack.in this instance, the order and method of inserting the plugs is veryimportant if optimum results are to be achieved by the repair. in thissituation, a plug 2b is first inserted diagonally from the valve seat soas to catch that portion of the crack in the corner of the waterchamber. Additional plugs such as 21, 22 and 23 are then successivelyinserted diagonally into the crack from the openings, each successiveplug overlapping and cutting off a portion of the previous plug untilthe entire length of the crack extending into the port has been filledand the base thereof has been cut off. A vertical plug 24 is theninserted from the deck surface so as to also catch the corner of thewater chamber and cut off the leading end of the previously diagonallyinserted plug, the first diagonal plug it and the first vertical plug 24combining to seal the crack around the corner of the water chamber.Additional plugs such as 25, 26 and 27 are then successively andoverlappingly inserted into the crack from the deck until that portionof the crack extending along the deck surface has been scaled and cutoff. Although the first vertical plug might sufiice to seal the verticalportion of the crack extending into the valve port, it usually does notengage sufficient metal to take all of the expansion out of the crack,and does not engage enough metal to prevent subsequent expansion duringuse. The diagonal plugs 2t to 23 are necessary not only to take up theexpansion, but are also necessary to cut off the base of the crack andprevent further extension thereof into the casting. It is preferable toinsert the diagonal plugs first, in order that the first vertical plugwill not be cut oil in part, as would be the case if the vertical plugswere inserted ahead of the diagonal plug and forms a stronger repair.The deck portion of the casting is subjected to a more severe strainduring use then are the walls of the port, and it is preferable to havethe vertical plugs en aging as much metal as possible to preventloosening thereof during use.

H63. 7 and 8 illustrate the method of repairing still er common type offailure, wherein the crack between two adjacent openings or valve ports29 and through the injector port 3% as well. For maximum efficiency, thedeck surface surrounding the injector port must be finished to ratherclose tolerances to permit accurate adjustment of the injector. In use,this area be comes somewhat uneven or irregular and this is intensifiedby any cracks which may occur. Therefore, to repa this type of failure,plugs 31 and 32 are inserted diagonally into the cracx from each valveport in the manner previously described to seal the crack and cut itoff. if more diagonal plugs are needed to complete the repair, they maybe added. A substantial portion of the decl; surface between the portsincluding the injector port 3b is drilled and tapped, and a largetapered plug 33 is inserted vertically therein so as to extend into theinjector chamber 34 and intersect and cut off a portion of the diagonalplugs El and 32 to form a secure engagement therewith. T he head of theinjector chamber is then reshaped to desired dimensions and the injectorport is rebored in the plug to the desired size.

FIG. 9 illustrates a type of failure peculiar to International typediesel heads, wherein a crack 40 commonly occurs in a somewhattriangular area defined by the valve ports 41 and 42 and the inclinedinjector port 43 wherein the crack usually extends from one of the valveports such as 41 along the deck surface between the other valve port 42and the injector port 43. In this particular head, the injector isattached to the head in such fashion as to create a strain on thecasting and tends to expand such a crack. A series of small interlacedplugs is usually not sulficient to take all of the expansion out of thecrack and resist the strain caused by the injector. Therefore, adiagonal plug 44 is inserted from one valve port 41 into the crack and alarge vertical plug 45 sutficient to take all of the expansion out ofthe crack is inserted so as to intersect and cut off a portion of thefirst diagonal plug 44. A plug 46 is then inserted diagonally from theother port to intersect the large vertical plug 45 and lock it in place.Small vertical plugs 47, d8, and 55) are then laced along the remainderof the crack to seal and cut it off.

Thus, from the foregoing description, the advantages of my invention arereadily apparent. By inserting tapered threaded plugs directly into thecrack the expansion or play is removed therefrom to prevent the plugsloosening during subsequent use. By overlapping and engaging the plugswith one another an uninterrupted body of new metal is provided in thecrack between the water chamber and the exterior surfaces: of thecasting so as to provide a fluid tight seal therebetween and byoverlapping the base or origin of the crack with one or more of theplugs, the crack is cut off and is prevented from further extending intothe casting. By inserting the plugs directly into the crack so as toextend substantially the entire length thereof, the number of plugswhich must be employed to accomplish the repair is substantially reducedand the risk of loosening previously inserted plugs is substantiallylessened. Finally, by first installing the diagonal plugs and thencutting them off with one or more vertical plugs, the vertical plugswhich receive the major portion of the strain during use engage amaximum amount of metal to provide a secure strong repair, and preventloosening of the vertical plugs during use.

It will, of course, be understood that various changes may be made inthe form, details, arrangement and proportions of the various partswithout departing from the scope of my invention.

What I claim is:

1. In metal castings such as the heads of internal combustion engineshaving adjacent openings such as valve ports extending into the interiorof the casting from the casting surface, a method of repairing a crackwhich extends between said adjacent openings, said method comprisinginserting at least two elongate metallic tapered threaded members intothe crack generally longitudinally thereof through suitably drilled andtapped holes originating in said openings interiorly of the castingsurface, at least one of said members originating in one of saidopenings and at least one other member originating in said adjacentopening, said members removing the expansion from the crack andthreadedly engaging at least a portion of one another, said engagedmembers providing a continuous mass of new metal in the crack effectinga fiuid tight seal, said members also overlapping and threadedlyengaging the sound metal adjacent the base of the crack, thereby cuttingoff the crack and preventing further extension thereof into the casting.

2. In metal castings such as the heads of internal combustion engineshaving an interiorly disposed fluid chamher and adjacent openings suchas valve ports and the like extending into the casting from the surfacethereof, a method of repairing a crack extending between said adjacentopenings said method comprising inserting at least two metallic threadedtapered members into the crack generally longitudinally thereof anddiagonal to the face of the casting, at least one of said membersoriginating in one of said adjacent openings, said members penetratingthe fluid chamber and engaging opposite sides thereof and overlappingand engaging the sound metal at the base of the crack to prevent furtherextension thereof into the sound metal, said members engaging at least aportion of one another and cooperating to take aosaaoo the expansion outof the crack and provide a continuous mass of metal in the crackeffecting a fluid tight seal.

3. In a cast metal head for an internal combustion engine having aninjector port disposed between the ad jacent valve ports, which injectorport communicates with an injector chamber interiorly of the casting,and fluid chambers enclosed within the casting and disposed between theinjector chamber and each of the adjacent valve ports, the method ofrepairing a crack extending between the valve ports and through theinjector port comprising inserting tapered members into the injectorchamber at such an angle as to provide a fluid tight seal, boring asubstantial portion of the face of the casting lying between the valveports, including the injector port, and tapping the hole provided, saidtapped hole extending from the face of the casting to the injectorchamber, inserting a threaded tapered member vertically into said tappedhole, said member extending into the injector chamber and engaging atleast a portion of the members originating in the valve ports,recontouring the injector chamber to the desired dimensions, andreboring the in ector port in said vertically inserted tapered threadedmember.

4. in metal castings such as the heads of internal combustion engineshaving adjacent ports extending inwardly from the face of said castingand fluid cooling chambers disposed interiorly of said casting andintermediate said ports, a method of repairing a crack extendinginwardly from the face of said casting and communicating with said portsand said chamber, said method comprising inserting a tapered threadedplug into said crack from one end thereof located adjacent one of saidports and generally longitudinally of said crack to engage and overlapthe entire length of that portion of the crack in direct communicationwith said chamber to seal same, said plug removing the expansion fromsaid crack and overlapping and engaging the sound metal adjacent thebase of said crack to prevent further extension thereof into the soundmetal of the casting.

5. In metal castings such as the heads of internal combustion engineshaving adjacent ports extending inwardly from the face of said castingand fluid cooling chambers disposed interiorly of said casting andintermediate said ports, a method of repairing a crack extendinginwardly from the face of said casting and communicating with said portand said chamber, said method comprising inserting tapered threadedplugs into said crack from opposite ends thereof adjacent the ports andgenerally longitudinally of said crack, and threadedly engaging bothsides of said crack to remove the expansion therefrom and seal saidcrack, said plugs overlapping and threadedly engaging each other andoverlapping the joint between the base of the crack and the sound metalto prevent further expansion of said crack.

6. The method set forth in claim 5, wherein the plugs engage the entirelength of that portion of the crack located in the chamber wall tocompletely seal the same and prevent escape of fluid therefrom.

7. In metal castings such as the heads of internal combustion engineshaving an opening extending inwardly into said casting from the facethereof and a fluid cooling chamber disposed interiorly of said castingadjacent said opening, a method of repairing a crack extending inwardlyfrom the face of said casting and communicating with said opening andsaid chamber, said method comprising inserting first tapered threadedplug means into said crack generally longitudinally thereof and intosaid chamber from said opening, and inserting second tapered threadedplug means into said crack and chamber from the face of said casting,said first and second plug means overlapping both sides of the crack andthe sound metal adjacent the base of said crack and thereby removing theexpansion from said crack and preventing further extension thereof intothe sound metal of the casting, said first and second plug means alsooverlapping and threadedly enhrs gaging each other and cooperating witheach other to seal said crack and prevent passage of fluid therethroughfrom said chamber.

8. The method set forth in claim 7 wherein said first plug means areinstalled before said second plug means vi hereby in installing saidsecond plug means said first plug means are cut off and threadedlyengaged by said second plug means.

9. The method set forth in claim 7 wherein said casting has a secondopening located adjacent said crack but not in communication therewith,and wherein third threaded tapered plug means are inserted into saidcasting from said second opening said third plug means being disposeddiagonally to the face of the casting and extending towards said secondplug means, whereby said second and third plu means intersect and arethreadedly engaged.

10. in metal castings such as the heads of internal combustion engineshaving adjacent openings extending inwardly from the face of saidcasting and a cooling fluid chamber disposed interiorly of said castingand intermediate said openings, 2. method of repairing a crack extendinginwardly from the face of said casting and communicating with said portsand said chamber, said method comprising inserting first taperedthreaded plug means into said crack from each of said openings in suchfashion that said plug means from opposite ends of said crack extendgenerally towards one another and into said chamber, and insertingsecond threaded tapered plug means into said crack and chamber from theface of said casting, said first and second plug means intersecting andbeing threadedly engaged and cooperating to seal said crack and preventpassage of fluid therethrough from said chamber, said plug means alsoengaging the sides of and removing the expansion from said crack andoverlapping the sound metal of the base of the crack to prevent saidcrack from extending further into the sound metal.

11. In metal castings such as the heads of internal combustion engineshaving adjacent ports extending inwardly from the face of said' castingand fluid cooling chambers disposed interiorly of said casting andintermediate said ports, a method of repairing a crack extendinginwardly from the face of said casting and communicating with said portsand said chamber, said method comprising inserting tapered threaded plugmeans into said crack generally longitudinally thereof from saidopenings whereby said plug means engage both sides of said crack andremove the expansion therefrom, seals the crack, and overlaps tbe soundmetal at the base of the crack to prevent further extension of the crackinto the sound metal.

12. In metal castings such as the heads of internal combustion engineshaving a plurality of openings adjacent to one another, a method ofrepairing a crack in said casting originating in one of said openingsand extending into the general area intermediate to and defined by saidopenings, said method comprising inserting tapered threaded plug membersinto said casting from said openings including the opening where thecrack originates, said plug means in said last named opening extendinginto said crack and generally longitudinally thereof so as to overbothsides thereof, and inserting second threaded tapered plug means intosaid casting from the face thereof in said area whereby said second plugmeans intersects, cuts oif and threadedly engages said first named plugmeans, said plug means cooperating to seal said crack, remove theexpansion therefrom and overlap the sound metal at the base of the crackto prevent further extension thereof.

13. In metal castings such as the heads of internal combustion engineshaving an opening extending inwardly from the face of said casting and afluid cooling chamber disposed interiorly of said casting adjacent toand separated from said opening by said casting, a method of repairing acrack extending inwardly from the face of said casting and communicatingwith said opening and said chamber, said method comprising insertingtapered threaded plug means into said crack generally longitudinallythereof from said opening and into said chamber whereby said plug meansoverlap both sides of said crack and the sound metal adjacent the baseof said crack and thereby removing the expansion from said crack andpreventing further extension thereof into the sound metal of thecasting, and sealing said crack to prevent the escape of fluid from saidchamber therethrough.

14. In metal castings such as the heads of internal combustion engineshaving an opening extending into said casting from the face thereof anda fluid cooling chamber disposed beneath the face of said castingadjacent said opening, a method of repairing a crack extending inwardlyfrom the face of said casting and communicating with said chamber andopening, said method comprising inserting tapered threaded plug membersinto said crack, at least some of said members being inserted into saidcrack from said opening generally longitudinally thereof so as tooverlap the sound metal adjacent the base of the crack and prevent itsfurther extension into the casting, said plug members also beingthreadedly engaged with each other whereby through said threadedengagement the plug members form a continuous body of new material inthe crack which provides a fluid tight seal and prevents the escape offluid therethrough.

15. In metal castings such as the heads of internal combustion engineshaving adjacent openings extending in wardly from the face of saidcasting and a cooling fluid chamber disposed interiorly of said castingand intermediate said openings, a method of repairing a crack extendinginwardly from the face of said casting and communicating with said portsand said chamber, said method comprising inserting first taperedthreaded plug means into said crack from each of said openings in suchfashion that said plug means from opposite ends of said crack extendgenerally towards one another and into said chamber, and insertingsecond threaded tapered plug means into said crack and chamber from theface of said casting, said first and second plug means intersecting andbeing threadedly engaged and cooperating to seal said crack and preventpassage of fluid therethrough from said chamber, said plug means alsoengaging the sides of and removing the expansion from said crack andoverlapping the sound metal of the base of the crack to prevent saidcrack from extending further into the sound metal, and wherein saidsecond plug means is installed after said first plug means whereby saidsecond plug means intersects, cuts off, and threadedly engages saidfirst plug means.

16. In metal castings such as the heads of internal combustion engineshaving adjacent ports extending inwardly from the face of said castingand a fluid cooling chamber disposed interiorly of said casting andintermediate said ports, a method of repairing a crack extendinginwardly from the face of said casting and extending between andcommunicating with said ports, said method comprising inserting a singlelarge tapered threaded plug into said crack from the face of saidcasting, said plug spanning the major portion of the length of saidcrack, and inserting tapered threaded plugs which are smaller than saidfirst named plugs into the crack generally longitudinally thereof fromeach of said openings whereby said smaller plugs are threadedly engagedwith said first named plug, said first and second named plugsoverlapping both sides of the crack and the sound metal adjacent thebase of said crack and thereby removing the expansion from said crackand preventing further extension thereof into the sound metal of thecasting, said plugs also cooperating with each other to seal said crackand prevent passage of fluid therethrough from said chamber.

17. In metal castings such as the heads of internal combustion engineshaving an opening extending inwardly from the face of said casting and afluid cooling chamber disposed interiorly of said casting adjacent toand separated from said opening by said casting, a method of repairing acrack in said casting extending inwardly from the face thereof towardssaid chamber, said method comprising inserting a single large taperedthreaded plug into said crack from the face of the casting whereby saidplug overlaps both sides of said crack and the sound metal adjacent thebase of the crack, thereby removing the expansion from the crack andpreventing further extension thereof into the sound metal of the castingand inserting at least one smaller tapered threaded plug into saidcasting from said opening whereby said smaller plug is disposeddiagonally to the face of said casting and intersects said first namedplug whereby said first and second named plugs are threadedly engagedwith each other, said plugs forming a fluid tight seal with said castingand preventing escape of fluid from said chamber through said crack.

References Qited in the file of this patent UNITED STATES PATENTS2,011,484 Harman Aug. 13, 1935 2,121,692 Hays June 21, 1938 2,361,701Michaels Oct. 31, 1944 2,482,925 Mercer Sept. 27, 1949 2,711,012 HarmanJune 21, 1955 2,751,671 Welch June 26, 1956

